ABSTRACT

Background – National guidelines recommend omitting SNB in older patients with favorable invasive breast cancer. However, there is a lack of prospective data specifically addressing this issue. This study evaluates recurrence and survival in estrogen receptor-positive/Her2− (ER+) breast cancer patients, aged ≥ 65 years who have breast-conserving surgery (BCS) without SNB.

Methods. This is a prospective, observational study at a single institution where 125 patients aged ≥ 65 years with clinical T1-2N0 ER+ invasive breast cancer undergoing BCS were enrolled. Patients were treated with BCS without SNB. Primary outcome measure was axillary recurrence. Secondary outcome measures include recurrence-free survival (RFS), disease-free survival (DFS), breast cancerspecific
survival (BCSS), and overall survival (OS).

Results. From January 2016 to July 2022, 125 patients were enrolled with median follow-up of 36.7 months [95% confidence interval (CI) 35.0–38.0]. Median age was 77.0 years (range 65–93). Median tumor size was 1 cm (range 0.1–5.0). Most tumors were ductal (95/124, 77.0%), intermediate grade (60/116, 51.7%), and PR-positive (117/123, 91.7%). Radiation therapy was performed in
37 of 125 (29.6%). Only 60 of 125 (48.0%) who were recommended hormonal therapy were compliant at 2 years. Chemotherapy was administered to six of 125 (4.8%) patients. There were two of 125 (1.6%) axillary recurrences. Estimated 3-years rates of regional RFS, DFS, and OS were 98.2%, 91.2%, and 94.8%, respectively. Univariate Cox regression identified hormonal therapy noncompliance to
be significantly associated with recurrence (p = 0.02).

Conclusions. Axillary recurrence rates were extremely low in this cohort. These results provide prospective data to support omission of SNB in this patient population

Trial Registration. ClinicalTrials.gov ID NCT02564848.

Keywords Breast cancer · Sentinel node biopsy · Age
over 65 · Estrogen-receptor positive · Breast conserving
surgery